I've been marveled by this code all morning. I already learned a lot but the most simple thing is still eluding me.

After playing with some palette settings I decided to use this as a display in my home, using an old tv connected to a cheap nuc. This tv can display up to 800x600 px. Changing the form GUI size is simple enough but for the life of me can't find how to change the rendering resolution. Any tips?